The optical information recording media (optical disks) are typified by optical disks such as CD, DVD, and BD, and are largely classified into three types of read-only type, write-once read-many type, and rewritable type according to the recording and reproduction system. Out of these, the recording system of the write-once read-many type optical disk is largely classified into, mainly, a phase change system in which the recording layer is allowed to undergo a phase change, an interlayer reaction system in which a plurality of recording layers are allowed to react, a system in which a compound forming the recording layer is decomposed, and a punching system in which recording marks such as holes or pits are locally formed in the recording layer.
With the phase change system, materials utilizing the changes in optical characteristics due to crystallization of the recording layer have been proposed as materials for the recording layer. For example, in Patent Literature 1, there is proposed a recording layer containing Te—O-M (where M is at least one element selected from metal elements, metalloid elements, and semiconductor elements). In Patent Literature 2, there is proposed a recording layer containing Sb and Te.
As the recording layer of an optical information recording medium of the interlayer reaction system, for example, in Patent Literature 3, there is proposed a recording layer in which a first recording layer includes an alloy containing In—O— (Ni, Mn, or Mo), and a second recording layer includes an alloy containing one element selected from Se and/or Te element, O (oxygen), and Ti, Pd, and Zr. Whereas, Patent Literature 4 proposes the following: a first recording layer: a metal containing In as a main component, and a second recording layer: a metal or a non-metal other than an oxide, containing at least one element belonging to the group VB or the group VIB are stacked; thus, recording is performed by the reaction or alloying due to heating.
As the recording layer of the system of decomposing the compound forming the recording layer, for example, in Patent Literature 5, a recording layer containing a nitride as a main component is shown. A study is conducted on materials for performing recording by decomposition of the nitride with heating, or an organic dye material.
As the recording layer of the punching system, the layer including a low-melting-point metal material has been studied. For example, in Patent Literature 6, there is proposed the layer including an alloy obtained by adding elements of the group IIIB, the group IVB, or the group VB to an Sn alloy. The present applicant also proposes, in Patent Literature 7, a recording layer including a Sn-based alloy containing Ni and/or Co in an amount within the range of 1 to 50 at %. Further, the present applicant proposes, in Patent Literature 8, a recording layer including an In alloy containing Co in an amount of 20 to 65 at %, or the In alloy further containing one or more elements selected from Sn, Bi, Ge, and Si in an amount of 19 at % or less.
[Citation List]
[Patent Literatures]
[PTL 1] JP-A No. 2005-135568
[PTL 2] JP-A No. 2003-331461
[PTL 3] JP-A No. 2003-326848
[PTL 4] Japanese Patent No. 3499724
[PTL 5] WO2003/101750
[PTL 6] JP-A No. 2002-225433
[PTL 7] JP-A No. 2007-196683
[PTL 8] Japanese Patent No. 4110194